The invention relates to the field of heating and cooling units and an improved modulator for use in re-directing the flow of liquid it the coil bank assembly. It is thought that the primary use of the invention would be in connection with cooling units since the primary purpose of the invention is to vary the number of active tubes, both upstream and downstream in a bank of tubes.
A coil assembly is really a bank of tubes, with each tube known as a xe2x80x9ctube rowxe2x80x9d or may be referred to as simply a xe2x80x9ctubexe2x80x9d in this application. There are both upstream and downstream section to each tube in the coil. Upstream sections (see 15 in FIG. 4) are those sections of the tube that carry the flow of water (or other fluid) from that end of the coil from where the supply manifold (see 1 in FIG. 4) is and then to the opposite end of the bank. Downstream sections are those sections that carry the flow back, i.e. from the opposite end of the bank back to the return manifold at the other end of the bank.
There are several ways in which these types of coils are used in the industry. For heating only; utilizing hot water, for cooling only; utilizing chilled water and for heating and cooling in what is called a change over system where the heating and cooling medium is changed depending on the needs. The modulator described herein is primarily intended to be used for the cooling application which means air conditioning units, primarily.
The inner and an outer valve together form the modulator section (which may be placed at 3, 4 or 5 in FIG. 4) of the present invention that is connected at one end of the tube bank or coil. Various tube sections of the coil are then in connection with ports on the outer valve. Ports on the inner valve correspond to those on the outer valve so water will flow into and out of the modulator and back through a downstream section of the tube bank.
The rotation of the inner valve varies with respect to the outer valve and this will limit the number of active upstream tube sections in a bank of cooling tubes and that in turn will allow the full travel length of the remaining tube sections to be used by the water flowing through the unit.
There is not believed to be any prior art systems that use a two port modulator with a varying individual tube flow control. Flow control is achieved by rotation of an inner and an outer valve that form the modulator and the alignment of apertures in each will control the flow of water through various tubes in the bank thus providing a novel system that will vary the travel path of the water in the coil in order to provide maximum heat transfer and a longer circuit path even when there may be less volume of water working in the coil.
The system is believed to find its greatest use in commercial building types of applications where large air conditioning units are used to cool buildings. The design of most such heating/ac units results in a bank of heat transfer tubes that is fed by an inlet manifold. The flow of water through the modulator will vary in response to a control device that in turn varies the number of active tubes so that the same volume of water can travel a longer circuit in the bank and thereby transfer more heat during its passage through the bank. This means that the water in the return line will run at a higher temperature and the chiller will operate more efficiently.
The present invention is believed to be useful as the use of the modulator will increase amount of heat transfer for a given volume of water.
Stratification of air within the bank will be reduced as will and this will result in improved performance of the unit as well. The unit is also believed to improve upon the design efficiency of existing units as the temperature differential between the upstream and downstream tube sections is more controllable.
An improved heat transfer coil assembly for chilled water units whereby a coil modulator is used in connection with the heat transfer coil assembly. The two port modulator is used to vary the number of active tube sections in cooling coil assemblies. The modulator comprises an inner valve, having valve ports in the sides of the valve, that rotates within an outer housing having openings that correspond to those ports in the inner valve. Apertures in the outer housing connect with upstream and downstream tube sections in the bank of tubes. As the actuator arm of the modulator is moved in response to changes in the temperature of the operating unit and/or the building to thereby control the flow of water through the unit. The actuator arms rotates the inner valve changing the orientation of the outer and inner valve ports and so as the actuator arm is moved further, this will vary water flow to more tubes in the bank.
It is an object of the invention to provide for improved heat transfer in a coil assembly heat transfer unit by passing water through more tubing under part load conditions of the system by altering the circuit (i.e. the flow path of the liquid) of the coil.
Another object of the invention is to increase the amount of heat transfer for a given volume of water in a heat transfer system by causing the water to travel further thus increasing the amount of heat transfer and raising the temperature of the water in the return line.
Another object is to improve efficiency in chiller systems by creating a greater heat transfer in a given volume of liquid to thereby improve the operating efficiency of chiller units.
Another object is to provide uniform distribution of liquid through coil banks of two or more coils in parallel thereby eliminating the need for circulator pumps to serve that purpose.
Another object is to minimize energy consumption through the elimination of those tertiary pumps used in conjunction with prior art coil arrangements in order to provide uniform distribution through the tube banks.
Other objects of the invention will become apparent to those skilled in the art once the invention has been shown and described.